Just curious. If fuel cell cars took off and became the majority, how would that effect humidity?

Question

I just wondered if it would make a difference since water vapor is the only emission.

Answer 1

It wouldn't. Humidity is determined by pressure and temperature.

Answer 2

Compared to water evaporating from oceans, rivers, lakes, leaves, animals and even the ground, water emissions from hydrogen-powered vehicles would be insignificant.  There would be virtually no effect.

Answer 3

Humidity is what we need more of in order to grow more plants outside and to help solve the problem of Global warming... The land surface of Earth, without Man's interference should originally have been all green. No Deserts.

Answer 4

Its a good question, but the additional water vapor in the atmosphere would just condense and turn into rain.

Answer 5

It wouldn't be affected... it is important to remember that a gasoline burning vehicle has water as an exhaust product, along with CO2, CO, and maybe some NOx

Answer 6

There would be no effect.  the contribution from hydrogen-powered cars is nil compared to that from lakes and rivers.  Humidity is more a function of weather conditions than the water vapor we generate.

Answer 7

Regular cars already put out lots of water vapor.  Water vapor and CO2.

If fuel cells are more efficient, it's possible they'll put out less water than regular cars already do!

Answer 8

almost not at all.

it'd be like boiling a large number of pots of water.

looks bad locally, but not noticeable on a large scale.

keep in mind, there is no free hydrogen.

if you need some, you take some water and separate the H2 from the O2.

when you burn it, or use it, you recombine it with the O2.

Answer 9

I have not seen anything scientific address this, but it is an interesting and valid question.  I expect it would raise the humidity some, but not as much as watering your lawn or crop irrigation.  Irrigation of any kind, whether on crops, golf courses or lawns and gardens raises the humidity tremendously, look at Phoenix and Las Vegas for example, the humidity in the cities is nearly that of any coastal area, yet only a few miles outside of them you are in the dessert with very low or now humidity.  

Good Question, hopefully some consider this before saying it is the only way to go.

Answer 10

It might briefly raise humidity but not enough to matter.  The nice thing about water (humidity) is that it condenses back out of the atmosphere as relatively harmless water.  Most other pollutants have a hard time getting out of the atmosphere and causing trouble.